package com.maserb.monitor.wechat;

import java.security.MessageDigest;
import java.util.Formatter;

public class MD5Util {

    private static String byteArrayToHexString(byte b[]) {
        StringBuffer resultSb = new StringBuffer();
        for (int i = 0; i < b.length; i++)
            resultSb.append(byteToHexString(b[i]));

        return resultSb.toString();
    }

    private static String byteToHexString(byte b) {
        int n = b;
        if (n < 0)
            n += 256;
        int d1 = n / 16;
        int d2 = n % 16;
        return hexDigits[d1] + hexDigits[d2];
    }

    public static String MD5Encode(String origin, String charsetname) {
        String resultString = null;
        try {
            resultString = new String(origin);
            MessageDigest md = MessageDigest.getInstance("MD5");
            if (charsetname == null || "".equals(charsetname))
                resultString = byteArrayToHexString(md.digest(resultString
                        .getBytes()));
            else
                resultString = byteArrayToHexString(md.digest(resultString
                        .getBytes(charsetname)));
        } catch (Exception exception) {
        }
        return resultString;
    }

    private static final String hexDigits[] = { "0", "1", "2", "3", "4", "5",
            "6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };
	
    public static String byteToHex(final byte[] hash) {
        Formatter formatter = new Formatter();
        for (byte b : hash)
        {
            formatter.format("%02x", b);
        }
        String result = formatter.toString();
        formatter.close();
        return result;
    }
    
    /** 
     * 将字节数组转换为十六进制字符串 
     * @param digest 
     * @return 
     */  
    public static String byteToStr(byte[] digest) {  
        // TODO Auto-generated method stub  
        String strDigest = "";  
        for(int i = 0; i < digest.length; i++){  
            strDigest += byteToHexStr(digest[i]);  
        }  
        return strDigest;  
    }  
      
    /** 
     * 将字节转换为十六进制字符串 
     * @param b 
     * @return 
     */  
    private static String byteToHexStr(byte b) {  
        // TODO Auto-generated method stub  
        char[] Digit = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};  
        char[] tempArr = new char[2];  
        tempArr[0] = Digit[(b >>> 4) & 0X0F];  
        tempArr[1] = Digit[b & 0X0F];  
        String s = new String(tempArr);  
        return s;  
    }  
}
